Gear box with free wheeling gear



April 2, 1940.

P. RAVIGNEAUX 2,195,783

GEAR BOX WITH FREEWHEELING GEAR Filed Dec. 29. :1957 2 Sheets-Sheet 1 AP 2 1940- P. RAVIGNEAUX v GEAR BOX WITH FREEWHEELING GEAR Filed Dec. 29, 1937 2 Sheets-Sheet 2 $.99 Fil Patented tpr. 2, l@

UNITED STATES PATENT OFFICE Application December 29, 1937, Serial No. 182,332

In France March 20, 1937 11 Claims.

The present invention deals with a gear box with complex epicycloidal trains suitable more especially for lautomotive vehicles. VIt comprises four or ve concentric members with totally intermeshed elements.

y The satellite of a first simple train formed with one pinion, one annulus with interior toothing and one satellite carrier, meshes with the satellite of another train,'which has the same satellite carrier. l

If the second train is identical with the rst one, there are five concentric members, the two pinions, the two annuli and the satellitecarrier. If in the second train the pinion or the annulus is eliminated, there are only four concentric members.

The system is called totally intermeshed because, on account of the meshings heretofore defined, when any one of the members is held stationary and inr themeanwhile any other one is set into motion, every other member rotates with a predetermined speed.

In the speed changing device which constitutes this invention, the satellite carrier is Aalways coupled with the propeller shaft, at least for all forward speeds.'

Two other members, which can be either a pinion or an: annulus, can be coupled individually with a driving shaft, by means of engaging devices, which generally are of the friction type.

These engagingdevices or clutches can be located in the flywheel, or in the gear box casingl or in any other location.

en the pinion and the annulus are alternately or simultaneously clutched and belong to the same simple planetary train, we shall from now on, in order to simplify the present description, call those planetary trains direct. On the contrary, when the` pinion and the annulus, to be clutched, do not belong to the same simple planetary train, we shall call them crossed trains.

This denomination is chosen because, when the two trains are complete, it is necessary, in order to obtain the second arrangement, for the pinion and the annulus of one of vthe trains to be located on opposite-sides with respect to thel pinion and the annulus of they other train, the satellite of one ofthe trains crossing the-zone where' the meshing of another train takes place.

The. planetaryv assembly herebefore defined gives, lwhen composed of four members, one ratio by letting in one clutch when the freemember is held stationary, and ygif/es moreover a direct speed by operating thel two clutches simultane- (cl. 'is-21o) ously, and at least one or two additional speeds can be obtained, if one of the clutchable members is held stationary, when the other onev is clutched. '4

As a rule, in such a transmission where the driving and the driven shafts have the same axis of rotation, only one of the clutchable members can be reached in order to be held stationary. Therefore, the possible speeds are 2+1|l=4 in number, positive or negative ones, of which one is direct.

When the motion is received by or transmitted from the gear box laterally, one more speed can be obtained, orfve speeds altogether. If the assembly is of ve members, two more speeds can be obtained by holding stationary the member which could not be reached in the four members assembly, and by operating one or the other clutch. The speed ratios obtained with the arrangement described before, being functions one of the other, it is necessary to compute the number of teeth in each case in order to obtain acceptable values; these values will consist generally of one negativeand several positive ratios, fractions or multiple of unity. A set of values in satisfactory graduation cannot be obtained in every case.

Several examples with numbers of teeth chosen for such results will be given hereafter. Obviously, these numbers may vary somewhat or be replaced by other ones proportional to the former numbers.

In the present description several arrangements -wi1l be shown in which one or several of the members will be held stationary by one way blocking devices, called free wheeling gears. This blocking by free wheeling gears of the members of a planetary gear box which must be held stationary and its application to the mechanisms dened previously lconstitute the `main characteristic of the present invention.' From the standpoint of kinematics a simple ratchet gear is the equivalent of a free wheeling gear; but, .unless several ratchetl gears act simultaneously, a transverse reaction is created, which does not occur with free wheeling gears, in which all loads are balanced.

In some particular cases, the ratchet gear alone will be sufficient.v In other cases, as will be explained later on, -a two-step blocking device will be designed, where a ratchet gear will be added `to a free wheeling gear in order to set free the g member controlled by the free wheeling. This result is obtained by discontinuing the blocking l effect of the free wheeling. Sometimes, on the contrary, the one-way blocking effect of the 'free wheeling acting on one of the members of the train will be completed by a ratchet gear acting in the opposite direction, with the result of blocking securely the rotating member. In the arrangements, which are the objects of the present invention, the ratchet gear will generally be designed to create reactions between parts which lare motionless relatively to each other only, and

even between motionless parts, as for instance, between a stationary part and the casing.

The present invention uses free wheeling gears or ratchet gears as abutments for the reactions of the members held stationary. Sometimes the free wheeling can be released, when it becomes necessary to set free the corresponding member in order to obtain the desired ratio. The solutions presented in this application and making use of ratchet and free wheeling gears were conceived in such manner that, in all the scale of the forward speeds, it is not necessary while shifting to higher or lower gears, to disengage or engage that member of the free wheeling which is adjacent to the casing and which we may call the outer rim of the free wheeling. This is of great value on account of the impacts which would occur, and one of the advantages exclusive to the epicycloidal gear boxes would disappear, viz., to free the driver from the necessity of engaging claws or gears rotating at different relative speeds. In this invention the engaging or disengaging of the outer rim takes place only when shifting from rst speed to the reverse. Out of this range, the driver effects all forward gear shifts by controlling a selector operating the clutches. Furthermore, the engagement or disengagement of the ratchet gears can be controlled by the same handle controlling the clutch selector, or by a separate lever or handle.

The main advantage of introducing free wheeling gears meeting the conditions previously stated, consists of eliminating all the planetary brakes, their controls, and the help of an outside energy, either to engage or dsengage them. 'I'his description is made, referringto two satellites only, simple or stepped ones, in each arrangement; but it is obvious that most of the time several sets of satellites will be used, which has the advantage of balancing the loads on the shafts, on the pinions and on the annuli, and of freeing them from any radial loads. The free wheeling devices can be of any type and it is possible to replace them by other equivalent mechanisms, capable of stopping a rotation in one way only. I call main pinions, the gears centered on the shaft with exterior toothing, and annuli, the gears centered on the shaft with interior toothing. The invention will now be described with reference to the accompanying drawings, which are given solely by way of example, andin which:

Fig. 1 is a section through a planetary gear box with four concentric members (2 pinions, 1 annulus and 1 satellite carrier) with crossed trains, giving three speeds (3rd direct) and reverse, and including one over running clutch that can be totally released in reverse, 'and one ratchet gear.

Fig. 2 is a diagram'of the pitch circles of the gears shown on Figure 1 with a side view of the control mechanism of the ratchet gears.

Fig. 3 shows this control in another projection.

Fig. 4 shows an arrangement with twoselectiveclutches.

Fig. 5 is the flat development of the selecting sleeve with axial drive.

Fig. 6 shows a gear box with ve members (two pinions, two annuli and one satellite carrier) with crossed trains, giving four speeds (3rd direct) and reverse, and including an over running clutch that can be totally released in reverse and one planetary brake. Fig. 7 is a modification with electromagne lbrake and one stepped satellite.

Fig. 8 is a further modication where the two clutches are of electromagnet type.

Fig. 9 shows a gear box with ve membersdirect trains-giving three speeds and one reverse and including three releasable ratchet gears.

Fig. 10 is a further modification, the mechanism being so designed as to transmit the rotation to a driven shaft located between the engine and -the`speed changing device, and the three releasable ratchet gears are replaced by two free wheeling gears and two ratchet gears.

Fig. 11 shows a gear box with four concentric members (two annuli, one pinion, one satellite carrier) with direct trains, giving three speeds and one reverse and including two releasable free wheeling gears and two non-rotating claws for stopping the corresponding member in both directions of rotation.

Fig. l2 is a gear box with 4 concentric members, having gears of the same nature, which are combined to operate as crossed trains. 'I'he release of the free wheeling gear is obtained by the axial sliding of a non-rotating claw.

Fig. 13 shows a gear box with 5 concentric members with crossed trains and stepped satellites, giving 5 speeds (5th direct) and one reverse, and including one releasable over running clutch, one non-rotating claw and one planetary brake.

Fig. 14 shows a modification with a simple satellite, where the reverse is obtained by chang ing the driven member, and which includes one releasable over running clutch, two ratchet gears and rotating claws for the reverse speed.

Figure 1 shows an epicycloidal gear box with 4 concentric members (2 pinions, one annulus and one satellite carrier) with crossed trains, and including one releasable free wheeling gear and one ratchet gear. The direct train comprises the pinion 3, the annulus 2, both meshing with the satellite 6, whose axis is supported by the ange 5, and the propeller shaft l0. This satellite 6 meshes with another satellite supported by the same flange, and the satellite Al meshes with another pinion I.

The pinion l is provided with clutching means; it is, for instance, fastened to the disc Il of a friction clutch, the coacting members of which are fastened to the crankshaft of the engine. In the same manner, the annulus 2 is coupled with the clutching member I2'. As annulus 2 does not belong to the simple planetary train made of wheels 3-6-2, the system is one of crossed trains. Between the pinion 3 which is not connected with the clutchingA members and the casing is located a free wheeling device 20, preventing this pinion from rotating in the direction opposite to the engine direction, but leaving it free to rotate in the same direction as the engine. When for the lowest speeds, the pinion l is clutched with the engine, the satellite carrier 5 rotating with the car wheels acting as reaction, the gear 3l has a tendency to rotate inthe opposite direction. As the free wheeling prevents this, it remains stationary and the transmission operates in the positive Il u "2,195,783 direction with a given gear ratio.y When the annulus 2 is clutched the same action takes place and the transmission operates again in lthe `opposite direction, but with another gear ratio. When the two clutches are operated -si l multaneously, this givesdirect drive; and nothing opposes the positive rotation in which gear drive.

30 on a ratchet-wheel 32, fastened to the annu- `3 is driven. The conditions of speed change, through the action'of clutches only, are fulfilled i lfor 3 forward speeds, one of which is direct lus 2, or any other mechanism preventing this annulus from rotating either'in the 'positive direction only or in both directions. Inorder to free the' gear 3 from'the action of the free wheeling deviceilil,I this freewheeling device 20 is released from the casing 80 on which it is supported. To secure this enact, the inner or outer rim of the free wheeling device, here the outer rim 2l, will be mounted so as to be able to rotate in the casing, and in order that the gear 3 may rest upon it, this outer rim will be held stationary by a pawl 3| acting on the ratchet gear 33.

lIn Figures 2 and 3, the action of the two ratchet gears, one of whichA is engaged when the other is free, can'be obtained by the same control. The ratchet gear is loose on axle 40. On the same axle is also loose, at the other end,

a lever 4I connected -with the ratchet gear 3I,'

through the -lever -42 and the link 43. When the two ratchet gears are set free, the relative position of each one of them with respect to the axle 40 is determined by a stop located onv axle 40 and shown by the pins 44 and 48 on Fig'- urel 3, toward which those ratchets are pushed by springs 45 and 41. At their other end, these springs bear against the control bushing itself,

on which the driver acts, when `he wants to vshift Afrom neutral to the forward or reverse speeds. The control extends from a vhandle to a lever 46 mounted on the axle 40. When Vthis lever 4tV is pushed toward forward speeds, corresponding to Figures 2 and 3, while also raising it, the pawl 3l begins to touch its ratchet wheel; then lever TIIIi moving further, the spring 41 is put in torsion, while at the same time the stop 48, supporting the pawl, loses its contact with the spring, while it is given enough clear-` ance in rotation to release itself from the ratchet wheel 33. Inversely, when acting in the opposite direction on lever-46, the pawl 30 engages with the ratchet wheel 32; its locating spring 45' serves as its operating spring. Itis preferable to use a one-way control, at least vfor foroward speeds, corresponding to the position shown on Figure 2. 'Ihe driver controls the lever 46 by an eccentric handle 49, mounted on axle 5|). The position of this handle can be such, for the Y forward speeds,'that the tension in spring 41 following numbers of teeth: u Pinion I=18 l Pinion 3:39

Annu1us2=75 Satellite 1:25 (arbitrary) f Satellite 6=18 Using combinations with three iigures, the first ,figurev giving the clutched member, the second driven member, ratios kx, Ica, lcs, kn. are obtained:

vWhen the transmission, instead of being effected concentrically to shaft I0, is done sidewise. as for instance through spur or bevel gear 8|, it ispossibletto lengthen the shaft carrying pin'- ion I and to brake'this wheel I with a drum 82, for instance. vThe extension of this shaft, the gear 8| and the drum 82 are-shown in dotted lines on Figure 1. additional speed, which is an overdrive is obtained. The speed ratio corresponding to the number of teeth chosen above is k4=1. 316.

Figure 4 shows an arrangement with two selector-clutches and Flgure 5 shows theplane de- *velopment of the sleeve selector. The assembly includes, in all, two friction-disc clutches of a well known type, but both are located in the same flywheel to obtain their respective release by the same control system. Disc II can be.

.the rotation axles of levers I1 and I3, for I1 inside of their connection to disc I3, and for I8, outside. It would be possible to arrange the discs and theycounter disks so that the pressing of the discs shall be in thesame direction, by having,

for instance, an intermediary partition installed in the ily-wheel. As the two clutches must be engaged one after the other, there isv provided a selector 60 controllable in a simple way, although it acts on rotatingparts, and I eliminate, wherever possible, any axial loads between stationary and rotating parts, while at the same time a. set of springs is compressed by an opposite load. These conditions are satisfied in the arrangement shown. The clutch levers of each set, such as I1and I8, when in the position of release, drive by meais of thel small levers I9, the rods 6I and 32, the ends of which slide away from the axle. When the clutch release takesv clutching. "With solid faces, on the contrary, these levers I1 or I8 must stay in the clutch-re-.

lease position, and no reciprocal action between lrotating and stationary parts results, when the pressure on the clutch pedal is released. The action of the springs results in a pressure be.- tween the ends of the rods 62 and 'the sleeve 60, both parts rotating together. As soon, as the levers of one system are lowered into the grooves of sleeve 60, this sleeve which operates as a selector is thus locked.- Instead of giving to the sleeve 60 a simple axial motion, a slight rotation cany be added to it, thus resulting in a helicoidal 1 motion, -which presents theadvantage of reduc- 5 ing the axial sliding movement.

Figure 5 shows the plane development of a selector designed for the arrangement of Figure 1. The solid and hollowedpathway correspondone the stationary member, the third one the Then by clutching 2, an u ing to the levers o! the system connected to disc II and to members denoted I on Figure 1, are represented above opposite to the reference I. Underneath is the view of the selector zone corresponding to the rods of the other system; and so on. The speeds are denoted by I, II, III, neutral by N, and reverse by R, at the top of the vertical lines. For the levers of system 1, there is used between the positions of 2nd and 3rd, speeds a continuous groove, connecting two holes. 'Ihis disposition is not essential but is given only as an illustration. In the system of speed change described, I must point out the possibility of shifting from direct drive to the lower speed without moving the selector handle from its direct drive position. When the clutch adjustment is made the member III first releases the clutch which does not enter into action in 2nd speed. When the clutch is released without pushing the pedal clear down, this gives the 2nd speed clutch, and the free wheeling gear renders the corresponding member stationary. It is then possible to shift again to direct drive merely by raising the pedal.

Figure 6 shows a gear box with 5 members (2 pinions, 2 annuli and one satellite carrier) with'direct trains, giving 4 speeds (3rd direct) and reverse, and including one releasable over running clutch and one brake. In this arrangement, with direct trains, pinion I is connected with one clutch element; the annulus 2, connected to the other, is part of the same simple train. The second train is connected to thev first train, as in the arrangement of Figure 1,-- on account of the presence of a satellite carrier l common to the two trains, and the meshing of the satellites together. The diagram of the. pitch circles has not been shown for this figure, or the following figures. 'I'he drawings show a zone, in which the satellites can mesh together, without touching either the pinion or the annulus of the other system; but in'order to make the description clearer, the two satellites are designed as projected in the plane of the drawings. In Figure 6, the meshing of the satellites occurs in the zone in which the second train meshes. as the satellites of the first train clears the two gears.

By using, for instance, the following numbers of teeth:

Pinion I:30 Pinion 3: 18 Annulus 3:64 Annulus 4:110 Satellite 8:17 Satellite 9: 46

Or by using the combination of speeds denoted by the conventional symbols, the following ratios are obtained:

These ratios are evenly scaled down and correspond to practical needs. The annulus l, in

all forward speeds. is prevented from rotating in sary in this case to provide for a device for the complete release of the free wheeling device; it will be suiilcient to lower upon this wheel a stop rod as shown at 30 on Figure A1. This rod will engage a ratchet wheel 32. For the 2nd speed geared down, and the 4th geared up, in which there are reactions in the opposite direction, I use for stopping the pinion 3, a brake, for instance, which can operate'in one direction or the other on a drum 34, or on a disc, or on any other stopping device of the friction type, operating in both directions.

Figure 7 shows an alternate construction to Figure 6. The braking is obtained by attracting an armature 10, mounted on gear 3. against the face of a stationary electromagnet 1I. To reduce the size of a'nnul'us I, satellite 9 represented on the preceding figure consists of two parts 3l and 9b as a stepped down satellite. By using for instance the following numbers of teeth:

YIII obtain, for the combinations of speeds (using the conventional symbols) the following speed ratios:

The stepping of satellite 9 permits reducing the diameter of the annulus diameter, and at the same time increasing the diameter of pinion 3, which must be of sufficient size to let the propeller shaft gof through. It has also the advantage, if desired, of obtaining within a smaller space a ilrst speed of a smaller ratio. The means, not shown, which controls the selector, can be coactive also with the control of the ratchet gear and of the electric contact which controls the 'stopping of wheel 3.

Figure 8 is an alternate to Figure '7, in which both clutching operations are performed by two electromagnets 'I2 and 13 respectively, coactive with armatures and 15, which are respectively fastened to pinion I and annulus 2. The other details of this figure are identical with the corresponding details of Figure 7. A

Figure 9 shows a gear box with 5 members, with ldirect planetary trains, giving 3 speeds and a reverse, and including 3 releasable ratchet gears This alternate is a modificationof the arrangements of Figures 6 and 7;.but the number of forward speeds is reduced to 3, and the brake on member 3 is eliminated. The result is the elimination of the overdrive, and pinion 3 is stopped vagainst rotation in the reverse direction only. As an illustration, all the one-way stops are obtained in this figure by ratchet gears. 'Ihe pawl 33 operates on the ratchet gear 34* and the pawl 33 operates in the negative direction for the forward speeds, 'and ratchet gear 31 operates in the positive direction for the reverse, and they enter in turn into action. I can use for the various gearings the same numbers of teeth as in the arrangement of Figure 7. The speeds are obtained with the same combinations During the operation of all forward speeds, the ratchet gears 35 and 36 enter into play as stops in the reverse direction.

In reverse gear, I raise thepawl 35 and put ratchet gear 31 into action. Ratchet gear 38 can remain engaged. I v c Figure 10 shows an alternate form to Figure 9,

with the mechanism designed for tr'ansmissionvof` the rotation to a .propeller shaft located between can be effected in the same manner as shown iny Figures 2`and 3; but this assembly is simpler since the control through levers 4I and 42 and the connecting rod 43 can be( eliminated. The driver may act directly 'on lever 83 secured to axle 40. Springs 45 and '41 are replaced by a single spring. The satellite carrier 5 surrounds the annulus 2 and drives a worn gear 84 meshing with gear 85, which, in an automobile, supports the differential. The driving of the worm gear by the satellite carrier may be obtained through acentering rsleeve 89, which rotates in the casing, by means of two sets of rotating claws 86 respectively fastened to parts 5 and 84.

Figures l1 and 12, the first having direct trains and the second l having crossed trains demonj strates that this invention can vbe applied to agear box having only 4 members, of which two are annuli and one is a pinion. Figure 12 is a modification of Figure 6' having'direct trains and shows a gear box with four concentric members (two annuli, only one pinion and one satellite carrier), giving 3 speeds and one reverse. It includes two free wheeling devices, one of which is releasable, and two nonrotating claws, with thel following numbers of teeth:

Pinion |=1a 'annulus 4:90 Annulus 2:90 Satellite as desired Satellite 6:36

The following speed ratios can be obtained, using the conventional symbols:

This arrangement is particularly convenient when a very low rst speed is' required. Annulus 4, which isl for all forward speeds stopped against reverse rotation by a free wheeling device 20, is held stationary in lreverse drive by the 'non- 'rotating claw 36a engaging with rotating claws by the operation of a rod 89 moving parallel to the axis. Figure 12 shows an assembly composed of the same elements as those in the arrangeoment shown in Figure l1; but these are combined to operate as crossed trains, as the clutchable wheels donot belong to the same simple train` Using, for instance, the following numbers of teeth:

Pinion I:18 Annulus v2:78 Satellite 6 as desired Annulus 4:54 Satellite 1:18

combinations represented The'following ratios can be obtainedwith The satellites can mesh in the zone in which pinion' I and annulus 2 are located, provided that satellite 6, the number of teeth of which is arbitrary, be taken suiliciently small to clear the teeth .of pinion I. The annulus 4, which must be held against anyI reverse rotation in all forward speeds, is mounted for free wheeling. The stationary part 2I of this free wheeling device is maintained in this state by rotating claws 328 engaged with claws 32h, secured to a stationary part 36". In reverse, these claws are disengaged by sliding 36b to the right. Annulus 2 can be held stationary at this time, for instance, by a band acting on a brake drum 81'.

Figure 13 shows a gear box, with 5 concentric members, the crossed trains and satellites of each set being stepped. It gives 5 speeds' (5th direct) and a reverse, and includes a releasable free by the conventional wheeling device, a non-rotating .claw and brake.

for instance, the following numbers of teeth: Pinion |=1s l Pinion 3:51" Annulus 4:90 Annulus 2:90

Satellite 121:43 Satellite 68:24 Satellite 7:29 Satellite 6:15

The following ratios can be obtained with the combinations represented bythe conventional symbols:

Annulus 4, which must be held stationary against reverse rotation in 1st and 3rd speeds is mounted with a free wheeling device releasable inreverse drive. lIn 3rd, 4th, and 5th, (forward) speeds,

this annulus can rotatefreely in the positive direction of rotation. Pinion 3, which must be held stationary against reverse rotation, yin 2nd and 4th speeds, could not be mounted with free wheeling device if it were disengaged during the change of combinations occurring in forward speeds,viz., in 1st and 3rd because at this time -it must be free to rotate in the reverse direction. This would not comply with the conditions imposed in the problem. Therefore, this pinion 'is connected to a lbraking device operating by friction. In this figure the braking is produced by attraction of armature 9|, secured to the pinion 3,by the elec` tromagnet 90. i

Figure 14 is an alternate formfto Figure 13, but with simple satellites. For the forward speeds, the operation is identical. 0n the contrary, the reverse drive is "obtained by Athe combination f (l-4-3) and requires a change in the coupling of shaft |01, which is connected4 by claws 92 with claws 93, in opposition to the v,forward speeds,

when the said shaft i is connected to the claws 94 secured to the satellite carrier 5 and of the shaft i0, using for instance, the following number of teeth:

Pinion |=16 -Pinion 3:26 Annulus 4:50 Annulus 2:58 Satellite 1:1'7 Satellite 6:16

The following ratios can be obtained with the combinations represented by the conventional symbols:

Annulus 4, whichmust be held stationary against reverse rotation in 1st and 3rd speeds, is mounted with a free wheeling device. In reverse drive the ratchet gear` is engaged, If 'it were desired in reverse drive to have the car in free wheeling, it would be possible to release the free wheeling of forward speed by a ratchet gear 96, whose motion can be controlled by the motion of ratchet 95.

In order to classify the various alternate forms of this invention, which have been described, it is pointed out that the arrangements with direct trains are those represented on Figures 6, 7, 8 and 9, and 10, which include two complete planetary trains, and the arrangement of Figure 12 which includes two annuli but only one pinion. Also, the arrangements with crossed trains are those represented on Figures 13 and 14, which include two complete planetary trains, and the` one represented on Figure 1, which includes two pinions and only one annulus, and Figure 13, which includes two annuli and only one pinion.

I claim:

l. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunning clutch acting upon the third wheel and permitting it to rotate only in the driving direction, planetary pinions adapted to connect the three said wheels in such manner that the rotation of one wheel will effect the rotation of the other twowheels when the planetary pinion carrier is in the stationary position.

2. A gear box comprising an epicyclic assembly comprising ay single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunning clutch acting upon the third wheel and permitting it to rotate only in the driving direction, a planetary pinion which meshes with the said annulus, with a pinion, and with a second planetary pinion engaging the third gear-wheel.

3. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunnlng clutch actingA upon the third wheel and permitting it to rotate only in the driving direction, a planetary pinion which meshes with the said annulus, with a pinion, and with a second planetary pinion engaging the third gear-wheel, which is a pinion.

4. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunning clutch acting upon the third wheel and permitting it to rotate only in the driving direction, a planetary pinion which meshes with the said annulus, with a pinion, and with a second planetary pinion en-' gaging the third gear-wheel, which is an annulus.

5. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adaptedfor all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunning clutch acting upon the third wheel and permitting it to rotate only in the driving direction, a selector for the two clutches whereby they may be simultaneously clutched in order to provide for the direct drive.

6. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one vannulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunning clutch acting upon the third wheel and permitting it to rotate only in the driving direction, a device for, releasing the third wheel of the overrunning clutch, and a device for holding, at least in the driving direction, the annulus adapted for clutching, in order to obtain a reverse drive by means of the same Wheels as are used for the forward drive.

7.` A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of 'at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunning clutch acting upon the third wheel and permitting it to rotate only in the driving direction,a device adapted for the release of the two clutches by a common control.

8. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward v this device being such that one unclutching action will take place before the other.

9. A gear box comprising an epicyclic assembly comprising a 'single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a driving device, an overrunnlng clutch acting upon the third wheel and permitting it to rotate only in the driving direction, a selector which isl rotatable with the motor and is adapted for axial movement, said selector comprising solid parts and cut-out parts, the solid parts serving for the radial support of members which are movable together with the devices of each clutching mechanism in order to prevent them from returning to the clutching position by the action of the springs employed for this clutching.

10. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are -rotatable about the axle of the planetary pinion carrier, these three wheels comprising at leastone annulus with internal teeth, means for clutching with the said annulus and with one of the said pinions by which they may be connected selectively with a` driving device, an overrunning clutch acting upon the thirdwheel and permitting it to rotate only in the driving direction, which is an annulus, the said epicyclic assembly further comprising a fourth gear-wheel consisting of a pinion engaging the second planetary pinion aforesaid, and means for stopping the said pinion.

1l. A gear box comprising an epicyclic assembly comprising a single planetary pinion carrier secured to a driven device adapted for all forward speeds, of at least three gear wheels, pinions and annuli, which are loose and are rotatable about the axle of the planetary pinion carrier, these three wheels comprising at least one an- `nulus with internal teeth, means for clutching POL RAVIGNEAUX. 

